Base materials in which a silicone-based release agent is coated onto the surface of a base material such as a plastic film or paper are widely used as release base materials.
However, the aforementioned base materials are easily charged, and tend to become even more easily charged when coated with a silicone-based release agent. Consequently, there has been a need to impart antistatic properties to these release base materials.
Although ionic conductive compounds such as surfactants have been widely used in the past as antistatic agents, since the conductivity of ionic conductive compounds is dependent on humidity, the antistatic properties thereof are unstable, while also having the problem of bleeding out from release base materials. Therefore, it is known to use π-conjugated electrically conductive polymers, in which electrical conductivity is not dependent on humidity and which do not cause bleed-out, as antistatic agents for imparting antistatic properties to release base materials.
π-conjugated electrically conductive polymers are substances that are insoluble and infusible, and cannot be applied to coating or extrusion lamination. Therefore, Patent Document 1 discloses a liquid dispersion of a π-conjugated electrically conductive polymer in which a polyanion is added as a combination dopant and surfactant.
However, higher definition levels have come to be required by displays in recent years, and further improvement of mounting speed has come to be required in the field of component mounting in particular. Consequently, there is a growing need for protective films used in optical applications and antistatic base materials used for electronic and electrical components.
In response to these needs, Patent Document 2 proposes a release base material that uses an addition curing-type silicone emulsion and a release agent containing a thiophene-based electrically conductive polymer. However, the release agent described in Patent Document 2 has low storage stability when stored in the form of an aqueous solution, resulting in the problem of it gelling in 2 to 3 days so that it can no longer be used. In addition, even if a coated film was attempted to be formed by forcibly coating the gelled release agent onto a base material, desired antistatic properties and release property were unable to be obtained.